PROJECT SUMMARY Nearly 35 percent of school-aged children are overweight and 19 percent are obese. This is a nearly five-fold increase in the percentage of obese children since the 1960s. Policy makers are aware of the childhood obesity problem, but developing effective obesity prevention interventions has been challenging. One reason is because weight gain among children is influenced by a complexity of factors. The focus of this study is on attributes of the commercial environment, built environment, and school environment that affect obesity among children and adolescents. The project involves strong quasi-experimental methods and follows a systems approach with the overall objective of generating actionable, policy-relevant information that can be used to prevent childhood obesity. Specifically, the project assesses the effect of access to a healthy diet, exposure to unhealthy food environments, availability of safe areas for vigorous play, and other characteristics of neighborhoods on childhood obesity. The study takes advantage of a unique dataset on the population of Arkansas public schoolchildren. Since 2004, public schools in Arkansas have been taking body mass index screenings. This allows investigators to track childhood weight status from the time children enter kindergarten through 10th grade. The proximity of schoolchildren to different types of food stores, restaurants, playgrounds and other features of the community are being carefully measured in order to determine whether and how much neighborhood characteristics affect obesity. Outcomes of the project will help policymakers better target interventions to those children that are especially at risk for obesity and will help community leaders understand what specific elements of neighborhoods place children at greater risk. Finally, the project is coordinated closely with the Community Development efforts of the project to facilitate coordination of efforts among communities with similar risks and thereby foster the creation of health-focused community systems among educators and health professionals.